Patent document 1 discloses technology in which the color of light from an emitting device is converted using a color conversion film and the resulting light is outcoupled to the outside. In this color changing medium (CCM) system, a method is known in the art which disposes a color filter (CF) in order to prevent a decrease in contrast which occurs when the color conversion film is excited and emits light due to external light, or to improve the chromatic purity of the color of light from the color conversion film (e.g. patent document 2).
However, since the color filter layer and the color conversion layer are formed in separate steps, production takes time, whereby cost is increased.
Patent document 3 discloses a method of reducing production cost by decreasing the amount of fluorescence conversion material used. However, the effects are insufficient.
Patent document 4 attempts to reduce cost by simplifying the production steps. However, since the color filter layer and the color conversion layer are formed in separate steps, the effects are not necessarily sufficient.
Patent document 5 discloses a method which includes applying a composition containing a color filter material and an organic fluorescent dye at one time, applying a transparent medium to the applied composition, and diffusing only the organic fluorescent dye into the transparent medium by heating. In the patent document 5, the organic fluorescent dye is diffused by heating. However, the organic fluorescent dye exhibits insufficient durability against irradiation of light. A photoluminescent inorganic nanocrystal exhibiting excellent light resistance may be incorporated into the composition instead of the organic fluorescent dye. However, since the photoluminescent inorganic nanocrystal cannot be diffused by heating, this measure cannot be applied to the above method.
[Patent document 1] JP-A-3-152897
[Patent document 2] JP-A-9-115668
[Patent document 3] JP-A-2003-229261
[Patent document 4] JP-A-2006-107761
[Patent document 5] JP-A-2002-151262
An object of the invention is to provide a composition capable of easily and efficiently producing a color conversion member including a color filter layer and a color conversion layer which contains a photoluminescent inorganic nanocrystal at a concentration which ensures a sufficient color conversion performance.
Another object of the invention is to provide a method capable of producing a color conversion substrate with high productivity.